• Journal of Electrochemical Science and Technology
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• v.7 no.1
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• pp.13-26
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• 2016

Nanoparticles (NPs), which have been investigated intensively as electrocatalysts, are usually synthesized by chemical methods that allow precise size and shape control. However, it is difficult to control the components and compositions of alloy NPs. On the other hand, the conventional physical method, sputtering with solid substrates, allows for facile composition control but size control is difficult. Recently, “liquid medium sputtering” has been suggested as an alternative method that is capable of combining the advantages of the chemical and conventional physical methods. In this review, we will discuss NP synthesis via the liquid medium sputtering technique using ionic liquid and low-volatile polymer media. In addition, potential applications of the technique, including the generation of oxygen reduction reaction electrocatalysts, will be discussed.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.269-272
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• 2004

The use of colloidal gas aphron (CGA), as an external oxygen carrier, provides a promising alternative to promote aerobic bioremediation of BTEX in the subsurface environment. CGA is a stable bubble supported by three surfactant layers and can supply oxygen below the soil surface uniformly due to its plug-flow characteristic. Since CGA has a hydrophobic layer that can act as a partitioning medium for hydrophobic contaminants it is known to facilitate desorption of soil-sorbed contaminants. In addition, bioaugmentation and biostimulation are possibly achieved by using CGA when generated from a solution containing BTEX-degrading microorganisms and appropriate nutrients. In this study, we presented the physico-chemical characteristics of CGA generated from a solution composed of microorganisms and nutrients. The applicability of CGA as an in situ aerobic bioremediation technology of BTEX will be further evaluated.

• Journal of the Korean Ceramic Society
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• v.23 no.1
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• pp.13-20
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• 1986

Zirconia soild electrolytes containing 4~10mol% of yttria were prepared by wet-blending of oxides and rea-ction-sintering, Sinterbility and degree of stabilization were optimized for the development of oxygen sensor. Fracture strength thermal expansion coefficient electrical conductivity and galvanic potential were measured and discussed with respect to the amount of ytria addition phase transformation microstructure and degree of stabilization. It was found that sintering and stabilization occurred when the composition was designed to be near the boundary region of $ZrO_2-Y_2O_3$ binary system. In such away a good zirconia solid electrolyte suitable for oxygen sensor could be developed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.11
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• pp.3630-3638
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• 1996

An experimental study has been conducted to explore the behaviors of the radiative ignition of polymethylmetacrylate(PMMA) in a confined enclosure such as the ignition delay time, PMMA surface temperature, the ignition location and the ignition process. In addition, the effects of hot wall orientation on the ignition delay and PMMA surface temperature were studied. When the hot wall is located at the bottom, ignition delay time is the shortest. Ignition surface temperature becomes the lowest for the hot top wall case. These are due to buoyancy effect. Since the radiative heat flux of hot wall is rather lower than laser source, the ignition is considered to be controlled by the mixing process. Therefore, the ignition location, where appropriate mixture of fuel and oxygen exists, occurs near the hot wall. The flame propagates along the hot wall where there exists sufficient oxygen.

• Journal of Yeungnam Medical Science
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• v.34 no.2
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• pp.174-181
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• 2017

Ferroptosis is a newly recognized type of cell death that results from iron-dependent lipid peroxidation and is different from other types of cell death, such as apoptosis, necrosis, and autophagic cell death. This type of cell death is characterized by mitochondrial shrinkage with an increased mitochondrial membrane density and outer mitochondrial membrane rupture. Ferroptosis can be induced by a loss of activity of system $X_c{^-}$ and the inhibition of glutathione peroxidase 4, followed by the accumulation of lipid reactive oxygen species (ROS). In addition, inactivation of the mevalonate and transsulfuration pathways is involved in the induction of ferroptosis. Moreover, nicotinamide adenine dinucleotide phosphate oxidase and p53 promote ferroptosis by increasing ROS production, while heat shock protein beta-1 and nuclear factor erythroid 2-related factor 2 inhibit ferroptosis by reducing iron uptake. This article outlines the molecular mechanisms and signaling pathways of ferroptosis regulation, and explains the roles of ferroptosis in human disease.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.2
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• pp.447-450
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• 2003

To clerify the cytotoxicity of reactive oxygen species in cultured hippocampal neurons of neonatal mouse, toxic effect was measured by MTT assay after cultured cells were incubated for 3 hours in the media containing 1～40 μM concentrations of H₂O₂. In addition, the protective effect of vitamin E was determined in these cultrures. Cell viability was significantly decreased in a dose-dependent manner after exposure of 10 μM H₂O₂ to cultured mouse hippocampal neurons for 5 hours. In the protective effect of vitamin E, vitamin E prevented the H₂O₂-induced cytotoxicity in these cultures. From these results, it suggests that H₂O₂ has toxic effect in cultured mouse hippocampal neurons and vitamin E has protective effect on the cytotoxicity induced by H₂O₂.

• Proceedings of the KIEE Conference
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• 1990.07a
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• pp.231-235
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• 1990

Soft magnetic silicon steels containing up to 6.5wt% of silicon were prepared by powder metallurgical processing and their magnetic properties were evaluated. The magnetic properties of P/M silicon steels are similarly affected by the silicon addition as those of conventional ingot processed ones but are also significantly affected by density and interstitial impurities particularly oxygen content. Magnetic flux density, $B_{10}$ and coercivity, Hc, tends to decrease with silicon content whereas maximum permeability, ${\mu}m$, decreases first and then increases rapidly above 5 wt% silicon. Increasing density also increases magnetic flux density and maximum permeability but reduces coereivity. The latter two properties are, however, affected more strongly with oxygen content.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.51-54
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• 2008

This study aims to devise and analyze a power generation system combining the solid oxide fuel cell and oxy-fuel combustion technology. The fuel cell operates at an elevated pressure, a constituting a SOFC/gas turbine hybrid system. Oxygen is extracted from the high pressure cathode exit gas using ion transport membrane technology and supplied to the oxy-fuel power system. The entire system generates much more power than the fuel cell only system due to increased fuel cell voltage and power addition from oxy-fuel system. More than one third of the power comes out of the oxy-fuel system. The system efficiency is also higher than that of the fuel cell only system. Recovering most of the generated carbon dioxide is major advantage of the system.

• Corrosion Science and Technology
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• v.16 no.4
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• pp.167-174
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• 2017

Bicarbonate/carbonate and molybdate anions have been characterized for their inhibitive effect on pitting corrosion of carbon steel in simulated concrete pore solution by using electrochemical tests such as electrochemical impedance (EIS) and linear polarization (LP). It was revealed that bicarbonate/carbonate has a weak inhibitive effect on pitting corrosion that is approximately one order of magnitude lower compared to hydroxide. Molybdate is effective against pitting corrosion induced by the concentration of chloride as low as 113 mM and can increase the pitting potential of a previously pitted sample to the oxygen evolution potential by the concentration of molybdate as much as 14.6 mM only. The formation of a $CaMoO_4$ film on the surface hinders the reduction of dissolved oxygen on the steel surface, reducing corrosion potential and increasing the safety margin between corrosion potential and pitting potential further. In addition, pore-plugging by $FeMoO_4$ as a type of salt film within pits increases the likelihood of repassivation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.5
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• pp.450-456
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• 2005

In this paper, the effect of adhesion properties of semiconductive-insulating interface layer of silicone rubber on electrical properties was investigated. The modifications produced on the silicone surface by oxygen plasma were accessed using ATR-FTIR, contact angle and Surface Roughness Tester. Adhesion was obtained from T-peel tests of semiconductive layer haying different treatment durations. In addition, ac breakdown test was carried out for elucidating the change of electrical property with duration of plasma treatment. From the results, the treatment in the oxygen plasma produced a noticeable increase in surface energy, which can be mainly ascribed to the creation of O-H and C=O. It is observed that adhesion performance was determined by surface energy and roughness level of silicone surface. It is found that at dielectric strength was increased with improving the adhesion between the semiconductive and insulating interface.